William A. Wallace

The cascading structure of typical spreadsheet formulae means that just about every spreadsheet is almost certainly wrong.

Solver Max provides a collection of optimization model examples in Excel (using the Solver and OpenSolver add-ins) and Python.

Overconfidence is one of the main causes of spreadsheet errors. Being informed about overconfidence leads to more accurate spreadsheets.

"Oh My God" my formulas are not working! This article covers most of the reasons for Excel formulas not working. And how to fix them.

Spreadsheet errors are reduced by using good design. Our students do three assignments to acquire good spreadsheet design skills.

Errors in the data, formulas, or manipulation of spreadsheets could be costly, even devastating.

Only a quarter of survey participants were satisfied with their spreadsheet testing. Their techniques are largely manual and lack formalism.

Good spreadsheets are essential for informing decision making. But most spreadsheets are not good. We help you make better spreadsheets.